This invention relates to a door lock apparatus for an automotive vehicle.
A known door lock apparatus for an automotive vehicle is as disclosed in the specification of Japanese Utility Model Application Laid-Open (KOKAI) No. 58-23886. This prior-art door lock apparatus comprises a base, a latch pivotally supported on the base, a ratchet pivotally supported on the base for engaging with the latch to limit the rotation thereof, an opening plate pivotally supported on the base by a rotary shaft the same a that of the ratchet for disengaging the latch and the ratchet, a locking lever rotatably pivoted on the base for disengaging the ratchet and the opening plate, and a connecting body pivotally supported on the locking lever via a vertically movable arm and passing through a window formed in the open plate so as to be capable of engaging with and disengaging from a contact edge formed on the ratchet. When the connecting body and the contact edge are in the engaged state, turning the opening plate causes the inner wall of the window to abut against and urge the connecting body so that it is turned about the portion connected to the locking lever. Owing to its turning motion, the connecting body abuts against and urges the contact edge to turn the ratchet. As a result, the latch and ratchet are disengaged so that a state is attained in which the latch is capable of being turned, i.e., in which the door can be opened. Turning the locking lever moves the connecting body up and down via the vertically movable rod to disengage the connecting body from the contact edge. Accordingly, the locked state is attained in which the door cannot be opened even if the opening plate is manipulated.
A problem encountered with the above-described door lock apparatus is that the centers of rotation of the ratchet and opening plate and the center of turning motion of the connecting body do not agree in the radial direction. As a result, when the opening plate is rotated, the connecting body urges the contact edge while sliding along it. This causes the contact edge to sustain an abnormal amount of wear and to develop a roughened surface. The surface roughness of the contact edge produces an unpleasant sensation when the door lock is operated.